Mansfield Toilet - difficulty flushing from the handle

I have a mansfield toilet that has become very difficult to flush by pushing down on the handle. I can open the lid and pull up on the flush ball from the ball seat but I can tell their is quite a suction there. Any suggestions as to how I can fix this would be appreciated.

First of all, allow me to ask this question? How old is the toilet and are all of the parts original? Mansfield toilets come standard with a special water saver flush valve which the handle fits through a loop and lifts a cannister up and down. Have you or anyone modified the tank in anyway? This is important to know because Mansfield even uses a special tank handle.

The toilet is the original toilet installed by the builder. It is approx 5 yrs old. Nothing has been done to it that I know of. It just started getting hard to flush about a month ago. To me it appears the suction is really strong when I compare it to the other same toilets in the house. That is why it is so hard for the handle to lift it up.

I replaced the red rubber ring that is called the flush valve seal. You can pick it up at home depot or Scottys etc for a couple bucks.. It will say "fits mansfield 210 & 211." The plunger/float flush valve sits on it. You want to make sure it goes back the same way. All you have to do is unscrew the center piece on the flush valve and loosen the flush lever and the ctr piece / flush valve will pull right off. Then the valve seal will pull right off.

Ensure when you replace the seal, that you clean the bottom of the flush valve itself..

replaced the red rubber ring that is called the flush valve seal. You can pick it up at home depot or Scottys etc for a couple bucks.. It will say "fits mansfield 210 & 211." The plunger/float flush valve sits on it. You want to make sure it goes back the same way. All you have to do is unscrew the center piece on the flush valve and loosen the flush lever and the ctr piece / flush valve will pull right off. Then the valve seal will pull right off.

Ensure when you replace the seal, that you clean the bottom of the flush valve itself..